Internal structure of 0.9 GHz microplasma

Journal Article · Wed Jun 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3592269· OSTI ID:21538396

Miura, Naoto; Hopwood, Jeffrey ^[1]

---

1. Tufts University, Electrical and Computer Engineering 161 College Ave., Medford, Massachusetts 02155 (United States)

Argon microplasmas generated at 0.9 GHz by a split-ring resonator form a single filament-shaped nonequilibrium glow discharge. The internal structure of these microplasmas is probed using laser diode absorption and imaging emission spectrometry. These two-dimensional diagnostics are then Abel inverted to reveal that the core of the filament has a strongly depleted central metastable argon population. The microdischarges are approximately 0.2 mm in width at 1 atm and expand with increasing input power between 0.05-1.5 W. The relative electron density and the Ar(4p) density are estimated from the emission detected by a CCD camera through various bandpass filters. Absolute Ar(4s) densities, on the other hand, are determined by Ar 801.4 nm absorption. The Ar(4s) profile transitions from center-peaked at low power (0.05 W) to center-depleted above 0.25 W, saturating at 10{sup 19} m{sup -3}. The electron density profile within the microplasma, however, remains center-peaked regardless of the power. The spatially-resolved gas temperature was estimated from the broadening of the Ar 801.4 nm absorption profile. The error in this gas temperature measurement due to the depletion of the metastable atoms is corrected using numerical heat transfer models and shown to be 1650 K if the plasma power is 1.2 W. Differences between the peak and average temperatures based on the nitrogen rotational spectrum are also explained using nitrogen emission imaging.

• OSTI ID: 21538396
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 11; Other Information: DOI: 10.1063/1.3592269; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABSORPTION
ARGON
CHARGE-COUPLED DEVICES
DENSITY
ELECTRON DENSITY
ELECTRON TEMPERATURE
EMISSION SPECTROSCOPY
GHZ RANGE
GLOW DISCHARGES
HEAT TRANSFER
ION TEMPERATURE
LASER RADIATION
LUMINESCENCE
NITROGEN
PLASMA DENSITY
PLASMA PRODUCTION
RESONATORS
SPECTRA
TEMPERATURE MEASUREMENT
TWO-DIMENSIONAL CALCULATIONS
ELECTRIC DISCHARGES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
ELEMENTS
EMISSION
ENERGY TRANSFER
EQUIPMENT
FLUIDS
FREQUENCY RANGE
GASES
NONMETALS
PHOTON EMISSION
PHYSICAL PROPERTIES
RADIATIONS
RARE GASES
SEMICONDUCTOR DEVICES
SORPTION
SPECTROSCOPY